Performance of Large CDMA Random Access Systems with Retransmission Diversity over Fading Channels

The random access systems, exploiting retransmission diversity (RD), over large random spreading CDMA channel subject to fading is investigated, under the assumption of infinite number of users and infinite spreading gain but with their ratio converging to a constant. The SIR, throughput and spectrum efficiency are analyzed. Simulation and numerical results show that RD exploitation can significantly increase the throughput and spectrum efficiency in channels both with and without fading.